Oven and hob on same radial circuit

[OldKettle]

Hi,
I currently have an oven on a dedicated 32A radial circuit with 6mm cabling.

The cable runs from the CU to a junction box, and then to the cooker switch (then 6mm onto the connection unit). The reason that there is a junction box is because somebody had previously spurred off a single switch (now disconnected).

I wish to add an induction hob.

The oven is rated at 4.9kW and the hob 7.4kW, and I have previously been advised that the circuit would be sufficient (up to 15kW total).

I just wanted to check that the fact that the circuit is radial doesn't affect its suitability for that load.

Also, the cable that currently runs from the CU to the junction box, is long enough that it could run direct to the oven socket. Given that, should I run the cable to the oven switch and then carry it on and terminate it at the hob switch (A) , or should I spur the hob from the junction box (B). (A) is certainly better for maintenance, but I just want to check that there are no other considerations.

Any thoughts would be much appreciated.

 

[jj4091]

https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=83894 this is a good explanation of your situation

 

[Londoner2]

I had this setup in my old kitchen, worked perfectly.

 

[EFLImpudence]

Are the hob and oven in different places or is it just your diagram?

You don't have to have two switches unless you want to.

 

[OldKettle]

Are the hob and oven in different places or is it just your diagram?

You don't have to have two switches unless you want to.

Thanks.

Yes, they are in different places, either side of a doorway. I did wonder whether I could get away with a single switch, with a short cable from the switch to the oven connection unit and a second longer cable (~6m) from the load side of the same switch to the hob connection unit, all 6mm cable.

That would be one less point of failure and it might also be preferable to have a single point of isolation that is away from the hob.

Would there be any problem with running the cable that distance to the connection unit?

 

[EFLImpudence]

I would think it will be fine. Presumably not a huge distance.

 

[AndyPRK]

I can understand now why you went for 2 swiches

 

[OldKettle]

I would think it will be fine. Presumably not a huge distance.

Thanks. The distance of the route from the switch to the furthest connection unit is 5.5 metres. After adding about 500mm to account for a getting through the ceiling void (joists are perpendicular to the route) I reckon 6 metres is pretty accurate.

 

[EFLImpudence]

You need to consider the total distance from the CU.

As long as it's an average size house it will be fine.

 

[OldKettle]

You need to consider the total distance from the CU.

As long as it's an average size house it will be fine.

Ah, right. The CU is actually on the other side of the wall, almost directly behind the oven, but the cable run is probably a total of another 5 or 6 metres before it will reaches the cooker switch. So 6 metres to the switch and another 6 metres from that switch to the second connection unit. So a total of 12 metres from the CU to the furthest connection unit, with the cooker switch at the halfway point.

Do that sound OK?

 

[EFLImpudence]

Yes, no problem.